HDR only works in 1080p, no 4k

Frozti

I bought a JVC LT-49MA875 last black Friday and I'm happy with the clarity and response time but was disappointed with the HDR. When I open a game on my xbox one x it switches to game mode and says 4k HDR. Yesterday I opened the same game I've been playing every day(fallout 76), with all the same settings on the console and TV as always yet it looked so much better. I noticed some settings appeared in the OSD that weren't available before so I came to the conclusion that HDR just now started working. When I restarted, no more HDR.

I disabled 4k and set it to 1080p and now HDR works every time, it doesn't change modes when I start the game. Enabling 4k again stops the HDR from working. I'm at a loss since it's advertised as 4k HDR, not one or the other and I'm using the cable that came with the console. I tried every HDMI input and another cable.

Everyone says the HDR in fallout is lame or that my TV doesn't do true HDR. I don't really care, I prefer the way it looks with the HDR on. The TV has very minimal settings and they all seem right, HDMI mode set to 2.1.

When I start a game in 4k it switches to game mode. Dynamic and PC mode disappear, along with dynamic contrast, unless I disable 4k.

I'd really like to have it running 4k and HDR at the same time and the fact that it worked once has really stumped me.

andym81

Theses low end HDR tv's are not very good. Need at least 600 -700 nits to notice the difference and local dimming

I own an smasung q9fn which is one of the best at HDR but even that s hit and miss depending on the content

Have u checked your HDMI cables

Frozti

The problem is not the quality of the HDR. I know it's bad. But I like it. The problem is that it simply does not work at all, unless 4k is disabled.

I'll check the pins on the cable tomorrow but it's brand new out of box and should be 2.1 high speed compliant.

next010

Sounds like a bandwidth problem, the HDMI port may not be a full speed port (even if it is a v2.0), when you turn off 4K there is sufficient bandwidth at 1080p to do HDR, with it enabled at 4K it cannot.

I looked at the manual and the HDMI mode "advanced 2.0" only supports YCC 4:2:0 at 4K/60Hz output. Xbox outputs in HDR 10-bit YCC 420 so it should work unless the TV doesn't really do that or doesn't have the bandwith.

On Xbox display settings change to below and see if that improves anything
video fidelity and overscan
display overrides = HDMI
video fidelity colour depth = 8-bit
colour space = standard

advanced video modes
allow YCC 422 if this is currently enabled disable it, but if it's not enabled give it a try.

Frozti

@next010   Thank you so much for your reply! Unfortunately these are the settings I had before and it doesn't seem to work. When I open a game it seems to display the splash screen in HDR then switches modes and disables HDR. I think I'll send a message to JVC asking if the TV is capable of both HDR and 4K simultaneously. While waiting for a reply I'll try my PC and PS4.

Is there anything else you can think of? If it turns out I cannot do both at the same time I'll be returning it and buying another.